Speed comparator



SPEED COMPARATOR Filed March 31, 1934 2 Sheets-Sheet l FIG-2 a I v 2Fla-5 I Q INVENTOR FOSTER E HILLIX a I BY I Fla-4' 4/ W 7 W ATTO EYJSPEED COMPARATOR Filed March 51, 1934 v 2 Sheets-Sheet 2 INVENTOR FOSTERF. HILLIX Patented Mar. 1, v 2,105,482

UNITED STATESPATENT OFFICE srsan coursas'roaFoster-lnillimliakewoodohiaaesignortolm dustrlal Baron Corporation,Cleveland, Ohio, a corporation of Delaware Application March 31, 1984,Serial No. 718,523

I This invention relates to a device for comtive of an apparatusembodying the invention; paring the speed of two rotating parts. MoreFig. 2 is a front elevation of the same with parts particularly theinvention relates to a speed broken away; Fig. 3 is a horizontal sectioncomparator for comparing the speed of a rotatthrough the apparatus; Fig.4 is a vertical sec- 5 ing part with the speed of a standard which istion taken along the line 4-4 of Fig. 2; Fig. 5 s rotating at a knownrate. I isa horizontal section taken along the line H Briefly, theinvention in its preferred form of Fig. 4; Figs. 6 and 7 are plans,partly in seccomprises two aligned rotatable surfaces, such as tion, ofa portion of the operating mechanism drums, one being driven at a knownconstant for the apparatus; Fig. 8 is a vertical section speed, as by asynchronous motor, and the other taken along the line 8-4 of Fig. 6; andFig. 9 is 10 being driven by the part the speed of which a similarsection showing the operating mechais to be measured. A spool-likemember is freely nism in a different position.

mounted so that one of its flanges rests against Referring to thedrawings, drums I and 2 are 7 each of the rotatable surfaces mentioned.The mounted on shafts 3 and 4, respectively, to rol6 rotatable surfaceshave a regularly varying contate therewith, ball bearings 5 beingprovided to tour, preferably that of a frustum of a cone, and reducefriction as much as possible. The drums Y the spool moves about untilits flanges are riding are rigidly fastened to their respective shaftsby on portions of the two surfaces which have the nuts 6 and drum l isadapted to be driven by same speed of rotation. The lateral movement anydevice, the speed of which is to be measured,

imparted to the spool by'this effect operates a through gear box 1' andshaft I. Drum 2 is 20 dial pointer or other indicating device toindidriven from a source of power having an abso- -cate the differencein speed between the unknown lutely con t i e of Sp Such 8-8 t ynspeedand the standard speed. chronous motor 9, through a coupling ii. The

In many industries itis necessary that machine drums i and 2 haveperipheries of such form 5 parts rotate at a definite constant rate ofspeed, that as the drums are rotated at speeds which otherwise theproduct will be unfavorably afarc'equal or not too different, theypresent bands fected. For example, in the textile industrlu it on theirperipheries which move at equal linear is required that variousthread-handling devices speeds. Preferably, the peripheries of suchoperate at an exact unvarying speed and particudrums regularly vary insuch a manner that the 0 larly is this-true in the artificial silkindustry diameter of one drum at any given distance where yarn is beingspun by a continuous process. from the end of the drum which is adjacentto The present invention aims to provide an appathe other drum is equalto -a corresponding diratus which measures the difference between themeter of the other drum at an equal distance speeds of two rotatingbodies rather than the from the end of said other drum which isadjaabsolute speed of one of them and thus extreme cent saidfirst-mentioned drum. The frustro- 35 accuracy can be obtained incomparing the speed conical form of the illustrated drums is an exof abody to be measured with that of a body ample of one shape of drum whichhas been known to be rotating at a constant speed. found preferable.

It is, accordingly, an object of the invention Mounted adjacent thesloping surfaces of the to provide an apparatus for accurately comparingdrums is a spool-like member or element I! hav- 40 the speed of arotating body with that of a known ing two flanges II and It which areadapted to standard. Another object of the invention is to contact withthe respective drum surfaces. This provide an amaratus 'inwhich thetendency for spool is mounted in lugs "projecting from the a freelyrotatable body to contact with two roface of a disk it lying in avertical plane in front tating surfaces at points having the sameperiphof the drums i and 2 and is accurately centered 4,5

erai speed is utilized to indicate any difference in for rotationbetween the lugs on cone point speed between the two surfaces. Furtherobjects screws ll secured in the lugs by nuts ll. 'A of the inventionwill in partbe obvious and will rectangular aperture is in the disk itpermits in partappear hereinafter. the flanges it and ll of the spool toproject so In the accompanying drawings there has been therethrough andcontact with the drum surso illustrated a preferred embodiment of theinvenfaces. The disk I is mounted in a gimbal ringtionbutitwillbeunder'stoodthatthesamelsilonballbearingsllandisthusfreetoturn capable of various modificationswithout departtherein in its own plane. The ring 2| is, in turn, ingfrom the scope of the invention. I mounted ,in' a yoke and lever 28, asmay be In said annexed drawings, Fig. l is a perspecseen in Fig. l, bymeans of cone point screws it so which are secured in the horizontalflanges 2d of the yoke and lever. The yoke, and lever 23 is fixed to ashaft 26 and turns therewith. It will be seen from the foregoing thatthe spbol i2 is free to move in a number of directions due to itsmounting. First, it is free to rotate on its own axis between the lugsl5, second, it may rotate about the axis of the disk l t, with which thelugs iii are integral, third, it may turn about an axis passing throughthe cone point screws 2d since the gimbal ring 2i is free to turn aboutthese screws, and fourth, it may swing with the yoke and lever 28 whichturns with the shaft 2%. As a result, the spool is free to seek aposition of equilibrium in contact with the surfaces of both drums whichrotate independently of each other.

If the two drums are now started rotating, one being driven by the partthe speed of which. is to be measured and the other being driven by astandard of constant speed, such as a synchronous motor, there will,perhaps, be some variation in the speed of the two drum surfaces, thisdifference being, however, small since the gear box '5 may be utilizedto bring the two speeds to approximately the same magnitude. When thespool is brought in contact with the two drums thus rotating, suchcontact being practically frictionless, it will hunt a position wherethe flanges l3 and M will contact with bands on the two drums having thesame peripheral speed. This is due to thefact that the spool can rotateat but one speed and the flange which is contacting with the slowermoving surface will tend to be retarded thereby,

while the flange which is contacting with the faster moving surface willtend to be accelerated thereby. This causes the spool, which is free toturn in the gimbal ring 2!, to dip at a slight angle to the axis of thedrums and the spool tends to move laterally toward the side whichequalizes the speed. The spool, then, will come to rest when in theposition where both flanges are being driven at the same rate of speed.The lateral movement thus imparted to the spool, being thus a functionof the speed differential between the two drums, can therefore beutilized to measure the difference in speeds.

.spool can, of course, be used.

The desirability of thus mounting 'the spool member for rotating abouta-plurality of axes will be apparent from the foregoing since the spoolmust be free to move under the varying forces applied to it by the drumsuntil it has found the position of equilibrium defined by relativelynarrow bands on the two drums having the same velocities. Other means ofmounting the .The effect of lateral movement of the spool member l2 asthe flanges l3 and I4 seek bands of equalspeed on the drums may betransmitted to an indicator which may be suitably calibrated to indicateany difference in speed between the two drums. This may consist, asshown, of a dial 21 with divisions marked thereon and a.

ingly in one direction or the other about the axis of the shaft 26 andthis movement will be communicated through he lever 29 to the gearsegment 31'! which turns the pinion 32 and the pointerlf Afterappropriate calibration of the dial 2'l, any'difference in speed betweenthe two drums will be accurately indicated on the dial and, since it isthe difference in speeds and not absolute speeds which is beingmeasured, a difference of two or three revolutions per minute will movethe pointer an appreciable distance, giving a fairly large reading. Ifthis difierence be applied to a constant speed standard rotating at, say1800 R. P. M., it will be apparent that an accuracy within 0.2% mayreadily be attained.

in order to prevent vibration of the needle 28 and delay in securing areading, a dash pot Si l has been provided, the same being connected toone of the lugs l5 by means of a rod 35 on the disk it, thus dampeningswings of the spool about the axis of the disk. This dash pot does notinterfere with the function of the instrument nor does it render itsluggish, the effect, on the contrary; being to speed up the reading.Movement of the disk H5 in the gimbal ring 21% is further limited bymeans of a pin 36 extending out from one of the lugs i5 and betweenstops 3'! and 38 to prevent the spool from assuming a position at sogreat an angle to the axis of the drums that equilibrium would notquickly be attained or would be entirely prevented. Movement of theyolze and lever 23 is also limited, as by cooperation of the lowergimbal-supporting arm of member 23 with the forked stop 39, to maintainthe spool opposite the drums.

In view of the fact that the spool member i2 is delicately mounted foraccurate and sensitive response to speed differentials between the twodrums, it will be obvious that the two flanges l3 and I4 should not bepermitted to contact simultaneously with drum surfaces which have a verylarge speed differential as would be the case, for example, if one drumwere rotating at full speed and the other were stationary. It is notfeasible to bring the two drums up to speed together and, consequently,means may be provided to position the spool out of contact with thedrums until such time as these are rotating at nearly the same speed.This condition will always prevail during measurements 'since theunknown may be geared up or down to bring the speed of the drumconnected with it into approximate equality with that of the standard.The clutch mechanism to move the spool into and out of engagement withthe drums includes the shaft 26 to which the rocking yoke and lever 23is pinned, the shaft being mounted in bearing 40 on the base plate 4| ofthe instrument.

This shaft passes through a lug 42 also mounted and mates with anothernon-rotatable jaw cam 46 carried by the collar 44. The cam 46 and collar44 are slidable on the shaft 26 and bear against a coil spring 41 whichin turn bears aioaasa 4| is rotated in a clockwise direction by means ofa lever l2 and link II ,pivotally attached This rotation of the camcauses the mating cam 40 to slide along the'shaft 28, on which it isprevented from turning by means of pins 4 which permit only lateralmotion of this cam. The collar 44 is thus forced against the spring 41and the motion, thus transmitted, pulls the shaft in the oppositedirection to the force exerted by the spring 49. This moves the yoke"again urges the spool away from the drums. I

I These cams are operated by a mechanism under the control of theoperator through a handle ll. This handle turns a shaft 84 which ismounted in bearings I1 and It onthe base plate 4i and to the shaft arepinned collars 58 and SI from which extend cams 02 and 03 respectively.The cam l2 engages a pin 84 mounted in forked link 53 straddling, shaftI. and clockwise turning of the shaft 50 by the handle 55 thus causesthe cam I to push the pin 64 to the right, as 'seen in Fig. 3, and withit the link 83 which turns the jaw cam 45 and brings the spool intooperative engagement with the drums land 2. When it is desired to returnthe spool to the inoperative position, the shaft It is turnedcounterclockwise by handle II, and a spring 65 pulls the link 53 to theleft, as seen in Fig. 3, restoring the jaw cam 45 to its originalposition. At the same time that the link 63 is being forced to the rightby clockwise rotation of shaft 5' when it is desired to take a reading,the-cam 63 engages a pin 68 in a link 61 and forces this link to theleft. The link operates a swltcli'in switch box 88 to start thesynchronous motor I running. A spring 69 placed on the link 61 betweenthe switch box 88 and collar ll aids in returning the link 61 to itsoriginal position and opening the switch when a .reading has beencompleted. In Figure 1, as in- '1 some machines being necessary.- Anexample of such a machine is that usedv for continuous spinning ofartificial silk where the filaments must be drawn from a spinning bathat a constantrate of speed. ,This means that one of the drums, in thepresent instance drum i, is always rotating' while the other drum, drum2, is rotated only when a'reading is desired. The sensitively mountedspool I! should not contact with the drums between readings since theun-- balanced force set up-by the one rotating drum would disarrange thespool mounting. Accord ingly, the above described operating mechanism isadapted to bring the stationary drum up to speed before the spool isbrought into contact with the drums. This is done'by first turning thehandle 5! clockwise through part of its throw, bringing cam 63 to someposition as that indicated in Figure 9, which forces the rod 61 to theleft and closes the switch it. The synchronous motor'9 then commences torotate and gradually brings the attached drum 2 up to a constant speed,say 1800 R. P. M. Due to the shape of cam '2, which is formed with adwell for part of its working surface, the pin 84 and link 53 are notmoved over by the partial throw of the handle BI which closes the switchII. A sufllcient period may now be allowed to elapse for the motor tocome up to speed and then the throw of the handle I! may be completed topush the link 53 to the right'and thus turn the jaw cam 45 which thenforces the mating Jaw cam 46 toward the spring 41 and thus moves theshaft 26 to bring the spool i! into contact with both drums. The speeddifferential between the two drums is then read off the dial 21, whichmay be of frosted glass illuminated by a light 12. The instrument isthen disconnected, by reversing the throw of the handle II, the firstpart of the throw removing the cam 62 from contact with the pin 64 andthus permitting the spring 65 to pull the link 58 to the left, whichturns the jaw cam 45 inthe reverse direction. The spring 49 will nowpull the shaft 28 in the opposite direction and force the spool out ofcontact with the drums. As the throw of the handle it is completed, thecam 63,

is similarly moved away from the pin 66 and the spring 69 vforces thelink 61 to the right and opens the switch to the motor 9. The throw ofthe handle 55 for disconnecting the instrument may, of course, becompleted without delay since the first portion of the throw moves thespool l2 out of contact with the'drums l and 2 and the motor may then bepermitted to come to rest without further attention. In connecting theinstrument, however,- the throw should not be completed until thesynchronous motor has come up to speed and means may be provided toprevent such completion of the throw until the proper time.

The operation of the device will be apparent from the foregoing but'abrief description of the principles involved will be given here. Whenthe two drums l and 2 are rotating at exactly the same'speed, the twobands where the flanges l3 and 14 of the spool contact, when the spoolis in zero position, will be running at the same rate of speed andthespocl will maintain a position equidistant from the edges of thedrums if the latter are of the same dimensions. Should the speed of onedrum difler from that of the other, however, these bands will assumecorrespondingly different speeds and one drum will tend to retard andthe other will tend to accelerate the rotation of the spool with theresult that the spool will instantly dip at a slight angle to the axisof the drums. In order to regain equilibrium, the spool, which ismounted for rotation about a plurality of different axes as stated, willrun toward one side or the otherin order to equalize the speed withwhich the two flanges are being driven. This position is one where theflanges can contact with bands on the respective drums having equalvelocities and, since the drums are now rotating at different speeds,the location of the respective bands will be at different distances fromthe adjacent faces of the tions. When the spool has finally come to restin its new position it has moved in a general lateral direction alongits own axis, either to the left or to the right, according as, thespeed of the- .pot is, hence, provided to dampen the oscilladrum whichis connected to the part Whosesneed is to he measured, is, greater orless than the constant speed of the drum connected to thesynchronous'motor. This lateral motion is communicated through the linkit to the gear segment ill which turns the pinion 3t and the pointer toeffect a movement or the pointer which is proportional to the lateralmovement of the spool. Adjustments can be made during calibration oi thedial since the link is ad justaoly connected to the gear segment 3 Sincethis lateral movement of the spool is a function oi the difference inspeed between the two drums, if any, there is thus provided an accurateindi cation of the speed of the part which is to he measured since thedifferential is based on the constant speed of the other drum connectedto a synchronous motor. if it be assumed that the speed of thesynchronous motor and its attached drum is icon it. P. DAL, then adifierence on the dial of two or three or more revolutions per min. ute,which can readily be read, indicates a speed of the other drum of 1800R. P. M. plus or minus the dial reading.

Since, in the operation of a speed comparator embodying the invention itis necessary that the rotating surfaces, when rotating at differentangular speeds afford paths moving at equal linear speeds, it isapparent that the magnitude of the sneed differential between the twodrums may he limited for a given pair of drums by the require= ment thatthey provide such paths of equal linear sneecls. The gear box i! may heprovided to bring the sgoeed differential between the two drums to sucha magnitudethat the paths of eoual speed on the surfaces of the drumswill lie within the hounds of the drums. For instance, it the angularspeed of the measured part varies from the standard angular speed by anamount larger than the speed differential which may he measured by thegiven drums, the ratio of the gears in the gear cos: 7] may be changedto the speed of the drum driven by the part the speed or" which is to bemeasured to near the speed of the drum driven by the standard, in whichcase the speed differential between the two drums be determined asalcove indlcatecl. The formula for determining the unknown speed willthen include the ratio of the gears in the gear box l. Great accuracythus can he obtained by means of an instrument em loodying theinvention, since only the small differential between the speeds of thetwo drums is measured, and the indicator is required to indicate onlythis differential instead of the ab solute speed of the part the speedof which is to be determined.

The instrument may be used for measuring the speed of rotationoi anypart or of any machine, one of the drums being connected throughsuitable gearing, or directly, to the rotating part to be measured andthe other drum being driven by a synchronous motor or other means whichprovides a standard of constant unvarying speed.

Obviously, with apparatus of this type it is possible to compare thespeeds of any two rotat ing parts or shafts, since it is not necessaryfor all applications of the invention that one drum be driven by astandard speed device. It its also at speeds hearing dd: i

i. aicasea apparent that the have" vantage in determining when two partsor are rotating at the it is intended that the patent shall cover, bysuitable expression the claims, whatever features of natentat-le noveltyreside in the invention.

What it claim is:

1. Apparatus for comparing the speed or a rotating part with a knownstandard which c0mprises a pair of drums i'laving a periphery varyingregularly in a direction axially oi the drum, means for driving one oidrums thepart the speed of which is heing'compared,

means for driving the other drum from a source having a known constantcreed of rotation, an element mounted PIOEELJLL lateral movementcontacting with each or drums, an in: dioator, and mocha? ""1 connectingsaid cator with said eleme i! to sit to the former the sp ed oi as dardwhich com-- 5 each having a direction axia ly pinquant rotatable St therotating parts to they correspond, said rotatable surfaces provi surfacepaths which move at equal linear s e ts when. said rotatable surfacesare rotated rotatable means in contact r said rotatable surfaces, saidrotatable means cemg capable, in response to differences in an u arspeeds of said rotatable surfaces, moves. e laterally of s rotatablesurfaces to n load. which said rotatable means contacts natl's of equallinear speeds on said. rotaahle surfaces; and indicatiu means responsivemovement of said rotataolemeans.

apparatus for comparing the speeds of rotation of two rota ng partscomprising twodrums respectively rotated about the same axis at speedshearing ratios to the speeds the rotating parts to which said drumsco-rre spend, the peripheries of said drums regularly varying in such amanner the diameter oi one drum at any given distance from the end ofsaid drum which is adjacent the other drum is equal to a correspondingdiameter of the other drum at an equal distance from the end of saidother drum which is adjacent said first-mentioned drum; an elementmounted for rotation and generally agdal movement contacting with eachof said drums; and indicating means responsive to generally axialmovement of said element.

5. Apparatus for comparing the speeds of rotation of two rotatin partscomprising two drums respectively rotated about the same axis at speedsbearing direct ratios to the speeds of the rotating parts to which saiddrums correspond,

said drums having conical nerinheries such that the diameter of one drumat any given distance irom the end of said which is adjacent the on mayhe used. to adat speeds bearing direct ratios to the speeds of therotating parts to which said drums correspond, .said drums havingconical peripheries such that the diameter of one drum at any givendistance from the end of said drum which is adjacent the other drum isequal to a corresponding diameter of the other drum at an equal distancefrom the end of said other drum which is adjacent said first-mentioneddrum, said drums being disposed with the maximum diameters thereofadjacent; a spool freely mounted for rotation and generally axialmovement, two flanges of said spool making point contact with theirrespective drums; and an indicator connected to said spool and adaptedto move in accordance with the generally axial movement thereof.

7. Apparatus for comparing the speed of a rotating part with a knownstandard which comprises two propinquant. rotatable surfaces eachvarying regularly in a direction parallel to the axis. of the surface,means for driving one of said surfaces from the rotating part and theother from the known standard, an element mounted for rotation anduniversal movement, including generally axial movement, contacting witheach of said rotatable surfaces, an indicator, and mechanism connectingsaid element with said indicator to move the latter in accordance withgenerally axial movement of the element.

8. In combination, two independently rotatable surfaces, a rotatableelement capable of generally lateral movement in response to differencesin the 'speeds of rotation of said rotatable surfaces positioned indriven contact with both of said rotatable surfaces, and means formoving said rotatable element into and out of contact with saidsurfaces.

vindicating differences in the speeds of rotation of said rotatablesurfaces of revolution.

' 10. In combination, two independently rotatable surfaces, a rotatableelement capable of generally lateral movement in response to dif-.-ferences in speeds of rotation of said rotatable surfaces positionedin driven contact with said rotatable surfaces, means for moving saidrotatable. element into and out of contact with said rotatable surfaces,and means responsive to generally lateral movement of said rotatableelement for indicating differences in the speeds of rotation of saidrotatable surfaces.

11. Apparatus comprising two propinquant surfaces of revolutionrespectively rotating at speeds bearing direct ratios to the speeds ofindependently rotating parts to which they correspond, at least one ofsaid surfaces of revolution varying progressively in diameter from aminimum to a maximum; rotatable means in contact with said surfaces ofrevolution, said rotatable means being capable, while in contacttherewith, of generally lateral movement across said surfaces ofrevolution in response to differences in speeds bf rotation thereof; andindicating means responsive to generally lateral movement of saidrotatable means to which such generally lateral movement iscommunicated.

12. Apparatus comprising two propinquant surfaces of revolutionrespectively rotating at speeds bearing direct ratios tothe speeds ofindependently rotating parts to which they correspond, each of saidsurfaces of revolution varying progressively in diameter from a minimumto a maximum; rotatable means in contact with said surfaces ofrevolution, said rotatable means being capable, while in contacttherewith, of generally'lateral movement across said surfaces ofrevolution in response to differences in speeds of rotation thereof; andindicating means responsive to generally lateral-movement of saidrotatable means to which such generally lateral movement iscommunicated.

13. Apparatus comprising two propinquant inversely disposed surfaces ofrevolution respectively rotating at speeds bearing direct ratios to thespeeds of independently rotating parts to which they correspond, each ofsaid surfaces of revolution varying progressively in diameter from aminimum to a maximum; rotatable means in contact with said surfaces ofrevolution, said rotatable means being capable, while in contacttherewith, of generally lateral movement across said surfaces ofrevolution in response to differences in speeds of rotation thereof-andindicating means responsive to generally lateral movement of saidrotatable means to which such generally lateral movement iscommunicated.

14. Apparatus for indicating relative speeds of rotation of two rotatingparts comprising two corresponding propinquant inversely disposedfrusto-conical surfaces respectively rotating at speeds bearing directratios to the speeds of the rotating parts to which they correspond;rotatable means in contact with said frusto-oonical surfaces, saidrotatable means being capable, while in contact therewith, of generallylateral movement across said frusto-conical surfaces in response todifierences in speeds of rotation thereof; and relative speed indicatingmeans responsive to generally lateral movement of said rotatable meansto which relative speed indicating means such generally lateral movementis transmitted.

15. Apparatus for indicating relative speeds oi rotation of two rotatingparts comprising two corresponding propinquant frusto-conical surfacesrespectively rotating at speeds bearing direct ratios to the speeds ofthe rotating parts to which they correspond; rotatable means in contactwith said frusto-conical surfaces, said rotatable means being capable,while in contact therewith, of generally lateral movement across saidfrusto-conical surfaces in response to differences in speeds of rotationthereof; and relative speed indicating means responsive to generallylateral movement of said rotatable means to which relative speedindicating means such generally lateral movement is transmitted.

16. Apparatus for comparing the speeds of rotation of two rotating partscomprising two propinquant rotatable surfaces respectively rotat- 0? therotating pea-ts to which eeid mtetebie em- ;teces correspenfl, each ofsaid; rotatable surfaces having pertipns thereof which move at diffeeentlinear speeds as; the surface rotates at any given angular speed; areteteble element cantata-tine both said rotatable surfaces and te:a'mve during mtetion there 3 m gaaeittom with.

ing at speeds beefing direct reties to the speeds we F. EHKLIX.

